pH-Triggered Transformable Peptide Nanocarriers Extend Drug Retention for Breast Cancer Combination Therapy.

Increasing the penetration and accumulation of antitumor drugs at the tumor site are crucial in chemotherapy. Smaller drug-loaded nanoparticles (NPs) typically exhibit increased tumor penetration and more effective permeation through the nuclear membrane, whereas larger drug-loaded NPs show extended retention at the tumor site. In addition, cancer stem cells (CSCs) have unlimited proliferative potential and are crucial for the onset, progression, and metastasis of cancer. Therefore, a drug-loaded amphiphilic peptide, DDP- and ATRA-loaded Pep1 (DA/Pep1), is designed that self-assembles into spherical NPs upon the encapsulation of cis-diamminedichloroplatinum (DDP) and all-trans retinoic acid (ATRA). In an acidic environment, DA/Pep1 transforms into aggregates containing sheet-like structures, which significantly increases drug accumulation at the tumor site, thereby increasing antitumor effects and inhibiting metastasis. Moreover, although DDP treatment can increase the number of CSCs present, ATRA can induce the differentiation of CSCs in breast cancer to increase the therapeutic effect of DDP. In conclusion, this peptide nanodelivery system that transforms in response to the acidic tumor microenvironment is an extremely promising nanoplatform that suggests a new idea for the combined treatment of tumors.

Property Enhancement of Waste Printed Circuit Boards Powders Reinforced Polypropylene by In Situ Magnesium Hydroxide Impregnation from Waste Lye.

Using alkali pretreatment can effectively remove residual variable-valence metals from non-metallic powder (WPCBP) in waste printed circuit boards. However, substantial amounts of waste lye are generated, which causes secondary pollution. On this basis, this study innovatively utilized waste alkali lye to prepare nano-magnesium hydroxide. When the dispersant polyethylene glycol 6000 was used at a dosage of 3 wt.% of the theoretical yield of magnesium hydroxide, the synthesized nano-magnesium hydroxide exhibited well-defined crystallinity, good thermal stability and uniform particle size distribution, with a median diameter of 197 nm. Furthermore, the in situ method was selected to prepare WPCBP/Mg(OH)2 hybrid filler (MW) and the combustion behavior, thermal and mechanical properties of PP blends filled with MW were evaluated. The combustion behavior of the PP/MW blends increased with the increasing hybrid ratio of Mg(OH)2, and the MW hybrid filler reinforced PP blends showed better thermal and mechanical properties compared to the PP/WPCBP blends. Furthermore, the dynamic mechanical properties of the PP/MW blends were also increased due to the improved interfacial adhesion between the MW fillers and PP matrix. This method demonstrated high economic and environmental value, providing a new direction for the high value-added utilization of WPCBP.

Valorization of Cheese Whey Powder by Two-Step Fermentation for Gluconic Acid and Ethanol Preparation.

Whey from cheesemaking is an environmental contaminant with a high biochemical oxygen demand (BOD), containing an abundance of lactose. Hence, it has the potential to be utilized in the manufacturing of bio-based chemicals that have increased value. A designed sequential fermentation approach was employed in this research to convert enzymatic hydrolysate of cheese whey (primarily consists of glucose and galactose) into gluconic acid and bio-ethanol. This conversion was achieved by utilizing Gluconobacter oxydans and Saccharomyces cerevisiae. Glucose in the enzyme hydrolysate will undergo preferential oxidation to gluconic acid as a result of the glucose effect from Gluconobacter oxydans. Subsequently, Saccharomyces cerevisiae will utilize the remaining galactose exclusively for ethanol fermentation, while the gluconic acid in the fermentation broth will be retained. As a result, approximately 290 g gluconic acid and 100 g ethanol could be produced from 1 kg of cheese whey powder. Simultaneously, it was feasible to collect a total of 140 g of blended protein, encompassing cheese whey protein and bacterial protein. Two-step fermentation has proven to be an effective method for utilizing cheese whey in a sustainable manner.

Exploring maternal-fetal interface with in vitro placental and trophoblastic models.

The placenta, being a temporary organ, plays a crucial role in facilitating the exchange of nutrients and gases between the mother and the fetus during pregnancy. Any abnormalities in the development of this vital organ not only lead to various pregnancy-related disorders that can result in fetal injury or death, but also have long-term effects on maternal health. In vitro models have been employed to study the physiological features and molecular regulatory mechanisms of placental development, aiming to gain a detailed understanding of the pathogenesis of pregnancy-related diseases. Among these models, trophoblast stem cell culture and organoids show great promise. In this review, we provide a comprehensive overview of the current mature trophoblast stem cell models and emerging organoid models, while also discussing other models in a systematic manner. We believe that this knowledge will be valuable in guiding further exploration of the complex maternal-fetal interface.

ß-Sitosterol Suppresses Lipopolysaccharide-Induced Inflammation and Lipogenesis Disorder in Bovine Mammary Epithelial Cells.

ß-sitosterol, a natural plant steroid, has been shown to promote anti-inflammatory and antioxidant activities in the body. In this study, ß-sitosterol was used to protect against lipopolysaccharide (LPS)-induced cell damage in bovine mammary epithelial cells, which are commonly studied as a cell model of mammary inflammatory response and lipogenesis. Results showed that treatment with a combination of LPS and ß-sitosterol significantly reduced oxidative stress and inflammation, while increasing the expression of anti-apoptotic proteins and activating the hypoxia-inducible factor-1(HIF-1α)/mammalian target of rapamycin(mTOR) signaling pathway to inhibit apoptosis and improve lipid synthesis-related gene expression. Our finding suggests that ß-sitosterol has the potential to alleviate inflammation in the mammary gland.

Circular RNA PGPEP1 induces colorectal cancer malignancy and immune escape.

OBJECTIVE: Colorectal cancer (CRC) is a prevalent gastrointestinal tumor globally. Circular RNAs (circRNAs) have been identified as regulatory players in the pathogenesis of CRC. However, it is unclear whether hsa_circ_0050102 (circPGPEP1) affects the malignant progression and immune escape in CRC. METHODS: Bioinformatics analysis and circRNA in vivo precipitation experiments were performed to analyze and identify circRNAs that mediate immune escape in CRC. Using luciferase reporter assay, RIP, RNA pull-down assay, and FISH, the interaction between circPGPEP1, miR-515-5p, and nuclear factor of activated T-cell 5 (NFAT5) was identified. The functional role of circPGPEP1/miR-515-5p/NFAT5 axis in CRC anti-tumor immunity was investigated by co-culture assay, CFSE assay, and flow cytometry of CRC cells and T cells. RESULTS: circPGPEP1 was a stable circRNA that was highly expressed in CRC. Functionally, circPGPEP1 silencing not only effectively inhibited CRC cell proliferation, migration, EMT, and immune escape and promoted apoptosis in vitro, but also inhibited CRC tumor growth and immune escape in vivo. In terms of the regulatory mechanism, circIGF2BP3 competitively upregulated NFAT5 expression by sponging miR-515-5p. Furthermore, functional rescue experiments showed that circPGPEP1 acted in CRC by regulating the miR-515-5p/NFAT5 axis. CONCLUSION: Collectively, circPGPEP1 exerts an oncogene role in CRC by regulating the miR-515-5p/NFAT5 axis.

New thoughts and findings on invasion and metastasis of pancreatic ductal adenocarcinoma (PDAC) from comparative proteomics: multi-target therapy

As one of the most aggressive malignant tumors, pancreatic ductal adenocarcinoma (PDAC) ranks as the fourth cancer-related mortality in the world. The extremely low survival rate is closely related to early invasion and distant metastasis. However, effective target therapy for weakening its malignant behavior remains limited. Over the past decades, many proteins correlating with invasion and metastasis of PDAC have been discovered using proteomics. The discovery of these proteins gives us a deeper understanding of the invasive and migratory processes of PDAC. This review is a systemic integration of these proteomics findings over the past 10 years. The discovered proteins were typically associated with the glycolytic process, hypoxic microenvironment, post-translational modification, extracellular matrix, exosomes, cancer stem cells, and immune escape. Some proteins were found to have multiple functions, and, cooperation between different proteins in the invasive and metastatic processes was found. This cooperation, and not just single protein function, may play a more significant role in the poor prognosis of PDAC. Therefore, multi-target therapy against these cooperative networks should be a primary choice in the future (AU)

Placental exosomal miR-125b triggered endothelial barrier injury in preeclampsia.

INTRODUCTION: Preeclampsia (PE) is an elusive life-threatening complication of pregnancy, and maternal endothelial dysfunction induced by components from the impaired placenta is a key hallmark of PE. Placenta-derived exosomes in maternal circulation have been correlated with risk of PE, however, the role of exosomes in PE remains to be determined. We hypothesized that placenta-released exosomes link the placental abnormalities with maternal endothelial dysfunction in PE. METHODS: Circulating exosomes were collected from plasma samples of preeclamptic patients and normal pregnancies. Endothelial barrier function was examined by transendothelial electrical resistance (TEER) and cell permeability to FITC-dextran assays in human umbilical vein endothelial cells (HUVECs). miR-125b and VE-cadherin gene expression in exosomes and endothelial cells were assessed by qPCR and Western, and the possible post-transcriptional regulation of miR-125b on VE-cadherin was detected by luciferase assay. RESULTS: We isolated placenta-derived exosomes in the maternal circulation and found that placenta-derived exosomes from preeclamptic patients (PE-exo) leads to endothelial barrier dysfunction. We then identified decreased expression of VE-cadherin in endothelial cells contribute to the breakdown of the endothelial barrier. Further investigations revealed increased exosomal miR-125b in PE-exo directly inhibited VE-cadherin in HUVECs, thereby mediating the adverse effect of PE-exo on endothelial barrier function. DISCUSSION: Placental exosomes link impaired placentation and endothelial dysfunction, thus providing new insight into the pathophysiology of preeclampsia. Exosomal miRNAs derived from placenta contribute to the endothelial dysfunction in PE and could be a promising therapeutic target for PE.

New thoughts and findings on invasion and metastasis of pancreatic ductal adenocarcinoma (PDAC) from comparative proteomics: multi-target therapy.

As one of the most aggressive malignant tumors, pancreatic ductal adenocarcinoma (PDAC) ranks as the fourth cancer-related mortality in the world. The extremely low survival rate is closely related to early invasion and distant metastasis. However, effective target therapy for weakening its malignant behavior remains limited. Over the past decades, many proteins correlating with invasion and metastasis of PDAC have been discovered using proteomics. The discovery of these proteins gives us a deeper understanding of the invasive and migratory processes of PDAC. This review is a systemic integration of these proteomics findings over the past 10 years. The discovered proteins were typically associated with the glycolytic process, hypoxic microenvironment, post-translational modification, extracellular matrix, exosomes, cancer stem cells, and immune escape. Some proteins were found to have multiple functions, and, cooperation between different proteins in the invasive and metastatic processes was found. This cooperation, and not just single protein function, may play a more significant role in the poor prognosis of PDAC. Therefore, multi-target therapy against these cooperative networks should be a primary choice in the future.

Acidic hydrolyzed xylo-oligosaccharides bioactivity on the antioxidant and immune activities of macrophage.

Xylo-oligosaccharides (XOS) prepared by the acetic acid hydrolysis of corncob were adulterated with many impurities including pigments, salts, and monosaccharides. Monosaccharides, acids, and most of the pigment were removed by a combination of decolorization, bipolar membrane electrodialysis and catalysis by Gluconobacter oxydans. These steps retain 90% of XOS in the acidolysis slurry. In this study, the effects of purified-XOS (PXOS) and crude XOS (CXOS) on the antioxidant and immune activities of macrophage were compared to verify the bioactivity of acidic hydrolyzed XOS, mainly focusing on the benefits of the purification process. PXOS was more effective in increasing superoxide dismutase activity and reducing malondialdehyde content, and thus had more potent antioxidant activity. In addition, PXOS could more efficiently promote the secretion of tumor necrosis factor-α, interleukin-6, nitric oxide, and interleukin-1ß by macrophage. All these data, suggest that the purification process contributed to improve the immunomodulatory activity of XOS from acidolysis slurry.

Precursor Chemistry Enables the Surface Ligand Control of PbS Quantum Dots for Efficient Photovoltaics.

The surface ligand environment plays a dominant role in determining the physicochemical, optical, and electronic properties of colloidal quantum dots (CQDs). Specifically, the ligand-related electronic traps are the main reason for the carrier nonradiative recombination and the energetic losses in colloidal quantum dot solar cells (CQDSCs), which are usually solved with numerous advanced ligand exchange reactions. However, the synthesis process, as the essential initial step to control the surface ligand environment of CQDs, has lagged behind these post-synthesis ligand exchange reactions. The current PbS CQDs synthesis tactic generally uses lead oxide (PbO) as lead precursor, and thus suffers from the water byproducts issue increasing the surface-hydroxyl ligands and aggravating trap-induced recombination in the PbS CQDSCs. Herein, an organic-Pb precursor, lead (II) acetylacetonate (Pb(acac)2 ), is used instead of a PbO precursor to avoid the adverse impact of water byproducts. Consequently, the Pb(acac)2 precursor successfully optimizes the surface ligands of PbS CQDs by reducing the hydroxyl ligands and increasing the iodine ligands with trap-passivation ability. Finally, the Pb(acac)2 -based CQDSCs possess remarkably reduced trap states and suppressed nonradiative recombination, generating a certified record Voc of 0.652 V and a champion power conversion efficiency (PCE) of 11.48% with long-term stability in planar heterojunction-structure CQDSCs.

Lithium Chloride Promotes Milk Protein and Fat Synthesis in Bovine Mammary Epithelial Cells via HIF-1α and ß-Catenin Signaling Pathways.

Lithium is one of the trace elements with many physiological properties, such as being anti-cancer, anti-viral, and anti-inflammatory. However, little is known about its effect on milk synthesis during lactation. Therefore, we selected different concentrations (5 mM, 10 mM, and 20 mM) of lithium chloride (LiCl) and assessed the effect of LiCl on bovine mammary epithelial (MAC-T) cells that underwent 4 days of differentiation induction. Moreover, we analyzed the effect of LiCl on the expression of genes related to milk fat and milk protein synthesis. Herein, LiCl (5-20 mM) significantly increased the expression of ß-casein, promoted mRNA expression and phosphorylated protein expression of the signal transduction molecule and activator of transcription 5ß (STAT5-ß), and inhibited mRNA and protein expression of suppressor of cytokine signaling 2 (SOCS2). In contrast, 5 and 10 mM LiCl significantly inhibited expression of SOCS3. LiCl at concentration of 5-20 mM enhanced phosphorylation level of mTOR protein; at 10 mM and 20 mM, LiCl significantly promoted expression and phosphorylation of downstream ribosomal protein S6 kinase beta-1 (S6K1) protein. Considering milk fat synthesis, mRNA expression of acetyl CoA carboxylase (ACC) and lipoprotein lipase (LPL) genes was considerably increased in the presence of LiCl (5-20 mM). Additionally, increased protein expression levels of stearoyl-CoA desaturase (SCD), peroxisome proliferator-activated receptor-γ (PPARγ), and sterol regulatory element-binding protein 1 (SREBP1) were observed at all LiCl concentrations tested. Subsequently, LiCl (5-20 mM) significantly promoted protein expression and phosphorylation of ß-catenin, while 10 mM and 20 mM of LiCl significantly promoted protein expression of hypoxia-inducible factor-1α (HIF-1α). Collectively, it has been shown that 10 mM LiCl can effectively activate HIF-1α, ß-catenin, and ß-catenin downstream signaling pathways. Conversely, at 10 mM, LiCl inhibited SOCS2 and SOCS3 protein expression through JAK2/STAT5, mTOR, and SREBP1 signaling pathways, improving synthesis of milk protein and fat. Therefore, LiCl can be used as a potential nutrient to regulate milk synthesis in dairy cows.

Osmotic stress tolerance and transcriptome analysis of Gluconobacter oxydans to extra-high titers of glucose.

Gluconobacter oxydans has been widely acknowledged as an ideal strain for industrial bio-oxidations with fantastic yield and productivity. Even 600 g/L xylose can be catalyzed efficiently in a sealed and compressed oxygen-supplying bioreactor. Therefore, the present study seeks to explore the osmotic stress tolerance against extra-high titer of representative lignocellulosic sugars like glucose. Gluconobacter oxydans can well adapted and fermented with initial 600 g/L glucose, exhibiting the highest bio-tolerance in prokaryotic strains and the comparability to the eukaryotic strain of Saccharomyces cerevisiae. 1,432 differentially expressed genes corresponding to osmotic pressure are detected through transcriptome analysis, involving several genes related to the probable compatible solutes (trehalose and arginine). Gluconobacter oxydans obtains more energy by enhancing the substrate-level phosphorylation, resulting in the increased glucose consumption rate after fermentation adaption phase. This study will provide insights into further investigation of biological tolerance and response to extra-high titers of glucose of G. oxydans.

Protective Effect of Hedyotis diffusa Willd. Ethanol Extract on Isoniazid-Induced Liver Injury in the Zebrafish Model.

Objective: This study aims to investigate the hepatoprotective effect and molecular mechanism of Hedyotis diffusa Willd. ethanol extract (HDWE) against isoniazid (INH)-induced liver injury in the zebrafish model. Methods: INH-induced liver injury model was established by adding an immersion bath of INH in 3 days post-fertilisation (dpf) healthy transgenic zebrafish with liver-specific fluorescence (L-FABP: EGFP). HDWE and INH were given to the zebrafish to observe liver morphology and pathology, fluorescence intensity, and the activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and superoxide dismutase (SOD), as well as the content of glutathione (GSH). The chemical composition of HDWE was analysed using high-performance liquid chromatography coupled with a quadrupole-time-of flight hybrid mass spectrometer (HPLC-Q-TOF-MS). The bioactive compounds, molecular targets and signalling pathways of HDWE were predicted using network pharmacology. Subsequently, molecular docking was adopted to analyze the affinities between the bioactive components and targets by Autodock. Finally, in vitro experiments were conducted to further verify the findings. Results: Our findings showed that HDWE had a remarkable protective effect on INH-induced liver injury in zebrafish. Twenty compounds in HDWE were identified. Nineteen hub targets were identified as possible targets of HDWE, and a compound-target-pathway network was constructed. Nine bioactive compounds, ten molecular targets, and seven key signalling pathways were found to play a pivotal role in the hepatoprotective effect of HDWE against INH-induced liver injury. In vitro studies revealed that the important bioactive compound quercetin-3-O-sambubioside (QSA) could significantly reverse INH-induced cell viability decreases and had a significant effect on the associated targets predicted by network pharmacology and molecular docking. Conclusion: In this study, through the research of hepatoprotective effect of HDWE and bioinformatics analysis, the bioactive compounds, important pathways and key molecular targets were discovered. These findings could provide scientific evidence for the use of HDW in liver injury and prove to help explore its efficacy and the mechanism of action.

Hydrogen Production on Pt/TiO2: Synergistic Catalysis between Pt Clusters and Interfacial Adsorbates.

Understanding the mechanism of hydrogen (H2) formation from the conversion of water (H2O) and renewables on TiO2 surfaces with cocatalysts via either photocatalysis or other catalytic processes is of significant importance to the successful design of efficient catalysts. Herein, we have investigated H2 production from H2O, CH3OH, and C2H5OH on a Pt cluster covered rutile (R)-TiO2(110) surface (Ptclut/R-TiO2(110)) to address the mechanism of H2 production. Experimental results demonstrate that surface adsorbates not only help H atom diffusion on Ptclut/R-TiO2(110) but also take part in H2 production directly. Further density functional theory (DFT) calculations suggest that H2 production on Ptclut/R-TiO2(110) occurs via a synergistic catalysis process between Pt clusters and interfacial adsorbates rather than a recombination reaction of H atoms on Pt clusters. This work provides new insight into H2 production from H2O and renewables with Pt/TiO2 catalysts, which may be applicable to H2 production on other Pt cluster deposited metal oxide catalysts.

Robotic Surgery in Rectal Cancer: Potential, Challenges, and Opportunities.

OPINION STATEMENT: The current standard treatment for locally advanced rectal cancer is based on a multimodal comprehensive treatment combined with preoperative neoadjuvant chemoradiation and complete surgical resection of the entire mesorectal cancer. For ultra-low cases and cases with lateral lymph node metastasis, due to limitations in laparoscopic technology, the difficulties of operation and incidence of intraoperative complications are always difficult to overcome. Robotic surgery for the treatment of rectal cancer is an emerging technique that can overcome some of the technical drawbacks posed by conventional laparoscopic approaches, improving the scope and effect of radical operations. However, evidence from the literature regarding its oncological safety and clinical outcomes is still lacking. This brief review summarized the current status of robotic technology in rectal cancer therapy from the perspective of several mainstream surgical methods, including robotic total mesorectal excision (TME), robotic transanal TME, robotic lateral lymph node dissection, and artificial intelligence, focusing on the developmental direction of robotic approach in the field of minimally invasive surgery for rectal cancer in the future.

Fabrication and Mechanical Properties of High-Durability Polypropylene Composites via Reutilization of SiO2 In-Situ-Synthesized Waste Printed Circuit Board Powder.

This paper focuses on the characterization of the physico-chemical properties, surface modification, residual copper content and in situ hybrid inorganic particle modification of polypropylene (PP) composites reinforced by waste printed circuit board powder (WPCBP). A series of WPCBP/SiO2 hybrids (TSW) were prepared by a sol-gel method at different pH values. Characterization results revealed the in situ generation of SiO2 on the surface of WPCBP, and showed that with an increase in pH value, the size of SiO2 particles increased gradually and the copper content decreased in the TSW powder. The mechanical properties, oxidation induction time (OIT) and thermal properties of PP composites were improved by reinforcement with TSW, which might be ascribed to the formation of serrated interfaces. This work not only develops a powerful method to enhance the properties of PP/WPCBP composites, but also provides an environmentally sustainable approach to the high-added-value reutilization of WPCBP.

Solution Annealing Induces Surface Chemical Reconstruction for High-Efficiency PbS Quantum Dot Solar Cells.

Colloidal quantum dots (CQDs) have a large specific surface area and a complex surface structure. Their properties in diverse optoelectronic applications are largely determined by their surface chemistry. Therefore, it is essential to investigate the surface chemistry of CQDs for improving device performance. Herein, we realized an efficient surface chemistry optimization of lead sulfide (PbS) CQDs for photovoltaics by annealing the CQD solution with concentrated lead halide ligands after the conventional solution-phase ligand exchange. During the annealing process, the colloidal solution was used to transfer heat and create a secondary reaction environment, promoting the desorption of electrically insulating oleate ligands as well as the trap-related surface groups (Pb-hydroxyl and oxidized Pb species). This was accompanied by the binding of more conductive lead halide ligands on the CQD surface, eventually achieving a more complete ligand exchange. Furthermore, this strategy also minimized CQD polydispersity and decreased aggregation caused by conventional solution-phase ligand exchange, thereby contributing to yielding CQD films with twofold enhanced carrier mobility and twofold reduced trap-state density compared with those of the control. Based on these merits, the fabricated PbS CQD solar cells showed high efficiency of 11% under ambient conditions. Our strategy opens a novel and effective avenue to obtain high-efficiency CQD solar cells with diverse band gaps, providing meaningful guidance for controlling ligand reactivity and realizing subtly purified CQDs.

Identification of metastasis-associated exoDEPs in colorectal cancer using label-free proteomics.

Exosomes are secreted nanovesicles consisting of biochemical molecules, including proteins, RNAs, lipids, and metabolites that play a prominent role in tumor progression. In this study, we performed a label-free proteomic analysis of exosomes from a pair of homologous human colorectal cancer cell line with different metastatic abilities. A total of 115 exoDEPs were identified, with 31 proteins upregulated and 84 proteins downregulated in SW620 exosome. We also detected 30 proteins expressed only in SW620 exosomes and 60 proteins expressed only in SW480 exosomes. Bioinformatics analysis enriched the components and pathways associated with the extracellular matrix, cytoskeleton-related pathways, and immune system changes of colorectal cancer (CRC). Cellular function experiments confirmed the role of SW620 exosomes in promoting the proliferation, migration, and invasion of SW480 cells. Further verifications were performed on six upregulated exoDEPs (FGFBP1, SIPA1, THBS1, TGFBI, COL6A1, and RPL10), three downregulated exoDEPs (SLC2A3, MYO1D, and RBP1), and three exoDEPs (SMOC2, GLG1, and CEMIP) expressed only in SW620 by WB and IHC. This study provides a complete and novel basis for exploring new drug targets to inhibit the invasion and metastasis of CRC.

One-Pot Ethyl Acetate Production from Ethanol Photooxidation on Rutile TiO2(110): Strong Photon Energy Dependence.

Ethyl acetate (EA) production from sequential ethanol (EtOH) photooxidation on a rutile(R)-TiO2(110) surface has been investigated by the temperature-programmed desorption (TPD) method at 355 and 266 nm. Significant EA product is detected under 266 nm irradiation, which is most likely to be formed via cross-coupling of primary dissociation products, aldehyde (CH3CHO) and ethoxy groups. On the contrary, EA formation at 355 nm is negligible. In addition, the initial rate of EA formation from EtOH at 266 nm is nearly 2 orders of magnitude faster than that at 355 nm. Quantitative analysis suggests that EA formation from sequential EtOH photooxidation on R-TiO2(110) is strongly dependent on photon energy or the energy of hot holes. This experimental result raises doubt about the traditional photocatalysis model on TiO2 where charge carriers relax to their respective band edges prior to charge transfer to adsorbates during the photocatalytic process, leading to no dependence on photon energy in TiO2 photocatalysis.